Stutter, Bucking, Bouncing tach (Yes I know typical but don;t know what to do now)

[ReckReason86]

OK So i have a 420 that is pretty much stock. The bouncing stutter began when i bought the car. The entire car shakes and bounces at a certain rpm. Usually around 3- 3.5K. I have replaced the coil pack( the first time i did this, it seemed to solve the problem it allowed me to redline for the first time thought it was solved, about 2 months later the problem came back, slowly and got worse over the time of 2 weeks. Have now changed Crank Sensor, plugs, wires, coilpack again. No CEL'S, nothing. Here is the weird thing, 3 weeks ago i replaced shifter cables, leaving the battery unplugged for 2 days, when i drove it again, the stutter was gone. Yesterday driving i felt the slightest bounce, so I stared at my tach wile driving, and sure enough there is a bounce, a tiny twitch i would say at max 100rpms, I know its going to get worse like last time. Any help is appreciated thanks (sorry for the paragraph)

 

[NOTORIO3030]

Since it when away when disconnecting the battery i would say something with your ECU is not working properly.

 

[ReckReason86]

Would it not throw out a code? Someone told me o2 sensor but i dont smell it running rich. My idle is high when i come to a stop like it holds a bit under 2 but once i completely stop it will come right down to normal, i figured a vaccuum leak somewhere

 

[ReckReason86]

ok just in case someone checks this thread out with similar problems, here is what i did that worked for me...

replaced all my intake gaskets, my tps, and all the emission sensors.

replaced my engine harness and all my grounds

and reset my timing..

as of now everything seems to be great